[Q-e-developers] Scalability of CP on BGQ (FERMI)

[Carlo Cavazzoni]

Dear All,

I've just completed a short scalability test of CP code
on FERMI (BGQ at CINECA). Here after you can find the first results.

Test case: CNT10POR8 (http://qe-forge.org/frs/download.php/63/CNT10POR8.tgz)

Number of  | Number of     | sec/      | OpenMP  | command line
real cores | virtual cores | iteration | threads | parameters
  4096      |  8192         |   231     |    4    | -nbgrp 2 -ntg 4 
-ndiag 256
  8192      | 16384         |   160     |    4    | -nbgrp 4 -ntg 4 
-ndiag 1024
16384      | 32768         |   131     |    4    | -nbgrp 4 -ntg 4 
-ndiag 1024
32768      | 65536         |    86     |    4    | -nbgrp 8 -ntg 4 
-ndiag 2048

it is not perfect, but it scale!
Consider that I've not yet done any specific BGQ
optimization, then there is a lot of room for improvement!
(Volunteer are welcome too!)

best regards,
carlo

-- 
Ph.D. Carlo Cavazzoni
SuperComputing Applications and Innovation Department
CINECA - Via Magnanelli 6/3, 40033 Casalecchio di Reno (Bologna)
Tel: +39 051 6171411  Fax: +39 051 6132198
www.cineca.it